Licensed wireless systems provide mobile wireless communications to individuals using wireless transceivers. Licensed wireless systems refer to public cellular telephone systems and/or Personal Communication Services (PCS) telephone systems. Wireless transceivers include cellular telephones, PCS telephones, wireless-enabled personal digital assistants, wireless modems, and the like.
Increasing demand for high data speeds and lower packet latency has required the mobile service operators to upgrade the existing Universal Mobile Telecommunication System (UMTS) cellular technology. Long Term Evolution (LTE) is one such upgrade which provides improved spectral efficiency, lower costs, and improved service.
The decision was made in the third generation partnership (3GPP) standards to not continue to define and support circuit switched (CS) services in LTE (i.e., to not support the use of the existing CS call control protocol and procedures for voice calls). Instead, the expectation was that operators would transition to the use of IP Multimedia Subsystem (IMS)-based voice service in tandem with their addition of LTE (i.e., “4G”) air interface and network technology.
In order to make the best use of the existing resources, access from the legacy core network infrastructure and services should be possible to provide CS services (e.g., voice and short message service “SMS”). This will allow avoiding a major switch in the voice call control paradigm as well as retaining the currently provided functionalities. Therefore, there is a need in the art to reuse parts of an existing technology, such as Generic Access Network (GAN), to provide CS services over the LTE networks.